Patent GB-1018948-A (GB)
IPC: G21C19/02
Abstract: 1,018,948. Fuelling reactors. COMMISSARIAT A L'ENERGIE ATOMIQUE. Aug. 2, 1963 [Aug. 3, 1962], No. 30811/63. Addition to 953,297. Heading G6C. A gas-cooled reactor comprises a concrete pressure vessel 12 enclosing a core 14 surmounted by a concrete slab 20 having closable passages (not shown) giving access to fuel element channels, a servicing chamber 18 being situated within the vessel 12 above the slab. An annular area 52 around the chamber 18 provides storage sites for cans 54 containing new or spent fuel elements. A radial arm 22 pivotally mounted on a central pivot 24 through a support 26 and supported by a circular track 28 has a circular toothed rack 30 engaging a gear 32 driven by a motor 34 through a shaft 36, this shaft being axially movable to disengage the rack. In case of failure, an identical further arm 22 is provided driven by a motor 34<SP>1</SP>, whereby the failed arm may be pushed by the other arm. The arms 22, 22<SP>1</SP> at their inner ends may be aligned with a short radial arm 50 also rotatable by a motor about the pivot 24, the arm 50 including a periscope. A machine 44 for transporting the cans 54 and for transferring the fuel elements to or from the core 14 is supported by a track on the arm 22, the machine including a television camera 57. The electricity supply for the machine 44 is taken from a cable which may be connected by means of a plug 40 carried by the arm 22, this cable being kept taut irrespective of the position of the machine by means of a drum. The connection with the plug is made remotely by a device 46. The machine 44 and cans 54 may be as disclosed in Specification 953,297. A tunnel 58 extends through the vessel 12, this tunnel being duplicated as a safeguard against failure, by an identical tunnel 58<SP>1</SP>. The tunnel 58 includes a passage 65 which may be sealed to form a lock by two rotatable doors 62, 64, Fig. 1 showing the' door 62 open and the door 64 closed. Tracks 67, 66, 68, 70, 72 are provided in the tunnel to enable the machine 44 to be moved from the arm 22 into the tunnel and transfer cans 54 between a position in the lock and the storage site 52. The lock may accommodate four cans 54, as shown. The tunnel extends to an elevator 60 including a cage 86 driven by a winch 87, the cage having two compartments provided with tracks 84, 85 either one of which may be aligned with the track 72. A track 82 in alignment with the track 72 normally supports a transfer machine 88 somewhat similar to the machine 44. The cans 54 of spent fuel elements are transferred from their position in the lock to an external position by loading them into the two compartments of the cage 86 by means of the device 88 and then lowering the cage. Cans of new fuel elements are introduced into the lock in a similar manner. The exact sequence of operations involving the opening and closing of the doors 62, 64 so that the elevator 60 is not in connection with the chamber 18 is described with reference to Figs. 3A-3F (not shown). A driving chain 90 in the tunnel 58 driven by a winch 92 serves to drive along the track a faultclearance machine introduced into the tunnel lock by the elevator cage 86 and the device 88. The chain 90 may drive the fault clearance machine on to the arm 22 where it is connected to an electric plug 42 on the arm 22 by a remotely controlled device 48. In the event of failure of the device 44 without immobilizing the arm 22, the latter is aligned with the track 67 so that the fault clearance machine may move on to the arm 22 and pick up the device 44 by means of a gripping device, the fault clearance machine returning with the device 44 to the lock, the plugs 40, 42 being disconnected. The transfer device 88 withdraws the fault clearance machine so that the machine is on the track 82 in the chamber 80 and the device 44 is on the track 85 in the cage 86. The fault clearance machine releases the faulty device 44 whereby the cage 86 may be lowered and the fault clearance machine placed in the track 85 by the device 88. The device 44 and fault clearance machine are now removed by the elevator 60. A new device 44 together with the fault clearance machine positioned on the two cage tracks 85, 84 are lifted by the elevator and a reverse sequence of operations are performed to position the new device 44 on the arm 22 whereupon the fault clearance machine is removed. These sequences of operations are shown in Figs. 4A-4N (not shown). If failure of the device 44 also immobilizes the arm 22, the arm 22<SP>1</SP> is aligned with the tunnel 58, the fault clearance machine is moved on to the arm 22<SP>1</SP> and the arm 22<SP>1</SP> is aligned with the arm 22, the fault clearance machine then moving the device 44 from the arm 22, across short arm 50 and on to arm 22<SP>1</SP>. The arm 22<SP>1</SP> is then re-aligned with the tunnel whereby the failed device 44 may be removed. This sequence of operations is described with reference to Figs. 5A-5E (not shown).